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Biological background: Molecular Biology Class web site: http://statwww.epfl.ch/davison/teaching/Microarrays/ Statistics for Microarrays
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Acknowledgements http://www.accessexcellence.org/AB/GG http://www.oup.co.uk/best.textbooks/bioch emistry/genesviihttp://www.oup.co.uk/best.textbooks/bioch emistry/genesvii Sandrine Dudoit, UC Berkeley Biostatistics Yee Hwa Yang, UC Berkeley Statistics Terry Speed, UC Berkeley Statistics and WEHI, Melbourne, Australia
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Two types of organisms * * Every biological ‘rule’ has exceptions!
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Timeline of Genetics Highlights
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http://www.stg.brown.edu/webs/MendelWeb/MWtoc.html Mendelian Genetics
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Human Chromosomes
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Human Chromosome Banding Patterns
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Chromosomes and DNA
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Cell Division -- Mitosis
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Cell Division -- Meiosis
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Crossing over and Recombination
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Mitosis and Meiosis Compared
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(BREAK)
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Nature (1953), 171:737 “We wish to suggest a structure for the salt of deoxyribose nucleic acid (D.N.A.). This structure has novel features which are of considerable biological interest.” DNA Structure Discovery
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DNA A deoxyribonucleic acid or DNA molecule is a double-stranded linear polymer composed of four molecular subunits called nucleotides Each nucleotide comprises a phosphate group, a deoxyribose sugar, and one of four nitrogen bases: adenine (A), guanine (G), cytosine (C), or thymine (T) The two strands are held together by weak hydrogen bonds between complementary bases Base-pairing occurs according to the rule: G pairs with C, and A pairs with T
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DNA A-type (140D) (low water content) DNA B-type (7BNA) (Watson-Crick form) DNA Z-type (2ZNA) (high salt concentration) Polymorphic DNA Tertiary Structures
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Genes are linearly arranged along chromosomes
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DNA Structure (overview)
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A nucleotide is a phospate, a sugar, and a purine (A, G) or a pyramidine (T, C) base. The monomeric units of nucleic acids are called nucleotides. DNA Structure
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Adenine (A)Guanine (G) (Purines) Thymine (T) (DNA) (Pyrimidines) Cytosine (C) Uracil (U) (RNA) Nucleotide Bases
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Nucleotide codes
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Base Pairing
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Proteins Proteins: macromolecules composed of one or more chains of amino acids Amino acids: class of 20 different organic compounds containing a basic amino group (- NH 2 ) and an acidic carboxyl group (-COOH) The order of amino acids is determined by the base sequence of nucleotides in the gene coding for the protein Proteins function as enzymes, antibodies, structures, etc.
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Amino acid codes
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Primary Protein Structure
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Multiple Levels of Protein Strucure ( Protein folding )
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Tertiary Structure of Sperm whale myoglobin (1MBN)
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(RT)
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Nature (1953), 171:737 “It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material.” DNA Replication
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The DNA strand that is copied to form a new strand is called a template In the replication of a double-stranded or duplex DNA molecule, both original (parental) DNA strands are copied When copying is finished, the two new duplexes, each consisting of one of the original strands plus its copy, separate from each other (semiconservative replication)
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Semiconservative Replication
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DNA Replication, ctd DNA synthesis occurs in the chemical direction 5’ 3’ Nucleic acid chains are assembled from 5’ triphosphates of deoxyribonucleosides (the triphosphates supply energy) DNA polymerases are enzymes that copy (replicate) DNA DNA polymerases require a short preexisting DNA strand (primer) to begin chain growth. With a primer base-paired to the template strand, a DNA polymerase adds nucleotides to the free hydroxyl group at the 3’ end of the primer. DNA replication requires assembly of many proteins (at least 30) at a growing replication fork: helicases to unwind, primases to prime, ligases to ligate (join), topisomerases to remove supercoils, RNA polymerase, etc.
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DNA Replication Fork
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DNA is unwinding DNA Synthesis
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RNA RNA, or ribonucleic acid, is similar to DNA, but -- RNA is single-stranded -- the sugar is ribose rather than deoxyribose -- uracil (U) is used instead of thymine RNA is important for protein synthesis and other cell activities There are several classes of RNA molecules, including messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA), and other small RNAs
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The Genetic Code DNA: sequence of four different nucleotides Protein: sequence of twenty different amino acids The correspondence between the four- letter DNA alphabet and the twenty-letter protein alphabet is specified by the genetic code, which relates nucleotide triplets, or codons, to amino acids
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Standard Genetic Code
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Variation of genetic codes T1: standard T2: vert mt T3: yeast mt T4: other mt T5: invert. mt T6: cil. etc nuc. T9: ech. mt T10: eup. nuc. T12:alt yeast nuc T13: asc. mt T14: flat. mt T15: bleph. nuc.
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Protein Synthesis
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